This invention relates to a diazodisulfone compound useful as a photosensitive material for deep ultraviolet (UV) light, electron beams, X-rays, etc. More particularly, the present invention relates to a diazodisulfone compound which generates an acid by irradiating with KrF excimer laser light (248.4 nm), ArF excimer laser light (193 nm), electron beams, X-rays, etc.
With recent higher density and larger scale integration of semiconductor devices, wavelengths used in exposing devices for minute processing, particularly for lithography become shorter and shorter. Now, KrF excimer laser light (248.4 nm) is studied. In order to use the KrF excimer laser as a light source, a resist material is required to act highly sensitively to light exposed.
One method for making the resist material highly sensitive is to contain therein a compound which has a property of generating an acid when exposed to light, that is, to use a so-called chemical amplified resist material [e.g. H. Ito et al: Polym. Eng. Sci., vol. 23, 1012 (1983)]. As the compound generating an acid by exposing to light (hereinafter referred to as "photoacid generator"), there are proposed onium salts such as allyl diazonium salts, diallyl iodonium salts, triallyl sulfonium salts (e.g. U.S. Pat. Nos. 4,491,628 and 4,603,101, Japanese Patent Examined Publication No. 2-27660, Japanese Patent Unexamined Publication No. 62-115440), 2,6-dinitrobenzyl tosylate [e.g. F.M. Houlihan, et al: SPIE, vol. 920, Advances in Resist Technology and Processing V, page 67 (1988)]. But, since these compounds used as the photoacid generator have aromatic rings, there is a problem in that resist materials containing these compounds lower transmittance for light. Further, in the case of onium salts, resist materials containing onium salts have a problem in that the resist materials are poor in solution stability during storage.
Therefore, a resist material overcoming the problem of poor solution stability caused by a property of photoacid generator, and improving transmittance for deep UV light and KrF excimer laser light is desired.